From German Published Patent Application No. 44 15 361, a method and a device for controlling an electromagnetic consumer is known. Such electromagnetic consumers are used especially for controlling fuel metering for internal combustion engines. In this application, a magnetic valve determines the injection duration and/or the beginning of injection.
In magnetic valves, a certain time span usually elapses between the control time and the reaction of the magnetic valve. This time span is usually designated as the switching time of the valve. This switching time depends on various parameters. Such parameters are, for example, the coil voltage and/or the coil temperature and/or the current flowing through the coil. A variable switching time of the magnetic valve, in turn, results in a variable injection duration and/or a variable injection beginning, and thus an injected fuel quantity that changes in an undesired manner.
From German Published Patent Application No. 195138 78, (U.S. Pat. No. 5,878,722) a method and a device for controlling an electromagnetic consumer is known. In the procedure described there, the duration of the control of the magnetic valve is corrected by a shut-off delay time of the current injection. This delay time is predefinable as a function of the instantaneous value of the current at the shut-off procedure.
Furthermore, it is known that, during shut-off, the mechanical switching times are functions of the shut-off current and the shut-off voltage. In order really to hold the influence of different shut-off currents to a low value, the current from the user is decommutated using the greatest possible extinction voltage. For this, components are required which have the appropriate voltage endurance. These components are comparatively expensive.